The present invention relates to an energy absorber for damping an impact on an element of the body of a motor vehicle, said energy absorber including essentially two support walls successively disposed with a number of single energy absorbing structural elements disposed in between.
Energy absorbing structures are provided in many areas in a motor vehicle body, to protect both, structures that are arranged spatially behind the energy absorbers, as well as protecting the passengers in case of a collision. Such energy absorbing structures or bodies are typically in the area of the bumper systems where, for example, energy absorbing elements or structures are integrated into the space between the mostly bowl shaped bumper and the bumper cross beam. These absorber areas are designed to absorb the energy of a collision, where the main emphasis, in case of a collision with a person, is to protect the person, while in a collision with another object, mostly the motor vehicle itself, or the structures that are being impacted upon are to be protected and to thus minimize the damage to the motor vehicle as much as possible.
To date, it has not been possible to optimally combine both afore-stated goals. Normally even today, the EPP-foam is still used as absorber material in order to comply with the legal regulation for the protection of pedestrians, for which this foam is well suited, although the foam has the disadvantage that it is too soft such that collisions at low speed with other motor vehicles, the foam does not absorb enough energy and as a result, damage occurs to the motor vehicle.
DE 100 42 560 B4 describes a support structure of a motor vehicle with a front end which is configured dual bowl shaped with an outer front end bowl shaped part which is a front end bumper, and an inner relatively rigid front end bowl shaped part which is the bumper cross beam and a deformation element which is disposed between the bumper and the bumper cross beam and has a foam structure.
In EP 1 577 168 A1 bumpers are described as energy absorbing component parts that are configured as blow molded hollow bodies that surround a foam filling on both sides.
The use of foam as an energy absorbing agent has the advantage that the foam is light and inexpensive. However, foam requires relatively much room with the additional disadvantage that the material, in case of an impact, does not revert 100% to its additional shape, which means that the energy absorbing material remains less effective as an energy absorber after each collision.
DE 102 387 A1 describes a bumper arrangement for a motor vehicle which is compact in structure and provides good pedestrian protection. An insert which is disposed between the bumper and the bumper cross beam has a plurality of nub-type deformation cups which when the insert is mounted are coordinated in such manner that upon impact, in case of a collision, while absorbing energy, the insert is plastic deformable through deformation of the deformation cups at the bumper cross beam with short block length. A drawback of this system is that the insert has to be configured specifically for the corresponding component assembly in the front end area, and is thus relatively complex in its construction. In addition, while the danger of injury for a pedestrian is reduced, the deformation cups, in case of a collision, react still relatively hard, whereby the motor vehicle is pretty well protected, however does not provide ideal pedestrian protection.
DE 10 2004 048 504 A1 describes an absorber body for a motor vehicle body element which consists of a plurality of side by side predetermined bending elements arranged under the outer skin of the body element. These predetermined bending elements are arranged set off in successive order between at least two support walls of the absorber body under the outer skin and are pre-formed such that in case of an impact, as a result, they follow a defined bending action. A body element of this type does not immediately give after subjected to static stress and at the same time when subjected to dynamic stress provides an effective protection against impact, e.g. when hitting a pedestrian. The energy absorbing effect can be controlled and adjusted by the bending angle, whereby for certain stresses substantially ideal absorption effects can be determined. However, this absorption body also has the drawback that a compromise must be sought between pedestrian protection and protection of the motor vehicle, which results in the fact that both goals cannot be optimally realized.
Thus, the problem persists to obtain an absorption body which fulfills both of these goals and which does not include the drawbacks of the prior art. It would therefore be desirable and advantageous to provide an improved absorption body to obviate prior art shortcomings and to provide protection both to the pedestrian and the motor vehicle.